Adhesive tape with convolutions tensioned under predetermined program



March 10, 1959 ADHESIVE TAPE WITH CONVOLUTIONS TENSIONED UNDERPREDETERMINED-PROGRAM B. B. BLACKFORD EI'AL 2,876,893

Filed Aug. 30, 1954 v so 5 6 4. 2 o

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WQTTZ RNEY ADHESIVE TAPE Vtli'i-i CGNVOLUTIONS TEN- SIONED UNDERPREDETERMINED PROGRAM Benjamin B. Blackford, Metuchen, and George W.McLaren, Jr., New Brunswick, N. 3., assignors to Johnson & Johnson, acorporation of New Jersey Application August 30, 1954, Serial No.452,996

8 Claims. (Cl. 20659) This invention relates to normally tacky pressuresensitive adhesive tape and particularly to rolls thereof processed tofacilitate their unwinding especially near the core.

it is conventional to wind surgical plaster, by way of example, thattype having cloth backing coated with normally tacky pressure sensitiveadhesive mass, by application of constant torque upon a winding mandrelto produce a roll of tape whose tension is greatest adjacent the axisabout which it is wound.

When the winding tension in a conventional roll of tape is such as toprovide in the outer convolutions a firmness suflicient to resistdeformation under normal handling, it has been found that the tension inthe inner convolutions, in many cases, is so great as tocause flow ofthe adhesive, its transfer to the back of adjacent convolutions, andsuch extreme difiiculty in unwinding as practically to render useless arelatively large section of the roll.

It has been discovered that if adhesive plaster with uncoated clothbacking is wound under tension below that which will cause flow of theadhesive mass through the cloth, such winding tension even after agingwill remain in the roll as an unwinding pattern, and that if a Windingprogram is employed characterized by the use of low tension in the innerconvolutions and higher tension in the outer convolutions, a roll oftape results having a firm exterior resistant to deformation and yetcapable of being unwound with the utmost ease down even to the very end.Indeed what is most surprising is that a roll of tape with such anunwinding pattern is easier to unwind as it approaches the inner end ofthe tape than it is at the outer end.

Other advantages of the improved roll of tape will be apparent fromthefollowing description in conjunction with the accompanying drawingswherein:

Fig. 1 illustrates a rollof pressure sensitive adhesive tape havingouter convolutions wound with greater tension than its innerconvolutions; and

Fig. 2 is a chart in which unwinding tension in the tape is plottedagainst yards of tape on the core.

In Fig. 1 there is illustrated a roll of surgical plaster 1t) wound upona core 11 and which includes a backing 12, preferably cloth, having onesurface coated with a layer of normally tacky pressure sensitiveadhesive 13.

In manufacturing such a roll of tape conventional methods may befollowed up to and including the slitting operation, but when the tapeis wound into rolls of appropriate length and width, a winding torque isexerted on the mandrel on which the tape cores are placed, which isvaried according to a pro-gram predetermined for the roll of tapethroughout its entire length, the predetermined program preferably beingsuch that the tension applied to the tape during the winding operationincreases from the core outwardly. By programing the winding, normallytacky pressure sensitive adhesive tape whose backing and adhesivecoating are such that wind-up tenatcnt sion can determine the unwindpattern of the tape, all the characteristics that experience showsdesirable in a roll of tape may be realized.

In selecting characteristics most desirable in a roll of tape,consideration should be given to the facility with which it may beunwound, its appearance, and its resistance to deformation duringhandling. Seemingly the most desirable unwinding pattern would be one inwhich there is no adhesion to the underlying convolution at all, butthat obviously is quite out of the question with pressure sensitiveadhesive tape. The optimum tension employed is that which will givegreatest ease in unwinding consistent with an absence of openingsbetween convolutions and a firmness at the exterior sulficient topreserve a good appearance and permit handling without unduedeformation.

In accordance with the invention the roll of tape preferably shouldunwind in an average pattern corresponding to a steady decrease inunwinding tension as the roll is unwound. Characteristics of such rollsof tape are illustrated by way of example in Fig. 2. The tape thererepresented had a backing of x 80 woven cloth and a coating of pressuresensitive adhesive 5 ozs. to the square yard. The preferred unwindingpattern is represented by curve a denoting a roll-of tape which in itsouter convolution has a tension of approximately 7 ozs. per inch ofwidth and gradually falls off to approximately 4V2 02s. per inch ofwidth near the core. The unwinding tension may go as high as 8 ozs. perinch of width in the outer convoluition and falling off to approximately5 /2 ozs. at the core, as illustrated in curve 12. While curve b wasarbitrarily selected as the upper limit of the tension program for acommercial product for a given service, and which has curve a as thenorm, quite obviously a higher tension program maybese'lected as theupper limit if desired. The lower limit for the particular productreferred to may be represented by the curve 0. This curve however shouldnot be regarded quantitatively since it merely represents for theparticular tape in question those tensions where it is expected spaceswill appear between convolutions. Obviously here too, tapes whoseunwinding program involves tension of a lower value, could be wound inaccordance with the invention so long as no spaces develop betweenconvolutions, since such rolls would be unsatisfactory from a commercialstandpoint. Sudden shifts in the tension level during winding are apt toinduce openings between convolutions during aging and accordingly shouldbe avoided.

It is thought that the upper tension limit for any given tape may befixed at that where the adhesive will start to flow and the masstransfer. The lower limit would be that tension below which spaces wouldstart to appear between convolutions.

The method or apparatus used fonwinding tape in accordance with theinvention is not important so long as the resulting rolls of tapethroughout their length have the unwinding tension characteristics ofthe predetermined program. The efficacy of any particular unwindingprogram may be quickly checked, however, by Winding up say a ten-yardlength of tape with the desired tension pattern obtained by theapplication at the end of the tape and throughout the wind of a weightappropriately varied to produce such pattern.

The tape may be wound by hand, varying the winding tension in accordancewith the desired program, or may be wound by winding apparatusespecially designed to give the desired winding program. A machinedesigned to wind tape with an increasing winding tension well suited forwinding rolls of adhesive tape in accordance with the present inventionis described and claimed in the co-pending application of Stanley C.Larson and John 3 J. Halliday, Serial No. 472,938, filed December 3,1954.

The invention has been illustrated in connection with one embodimentthereof although many modifications are within its spirit. It is to belimited therefore only by the scope of the appended claims.

What is claimed is:

1. A roll of normally tacky and pressure sensitive adhesive tape withadjacent convolutions in face-to-face contact and including a wovencloth backing having on one side, a pressure sensitive adhesive coatingand, on the other side, an absence of any coating that would tendsubstantially to alter the discontinuity normally presented by such acloth backing by virtue of its weave, said roll of tape between theadhesive coated sides of the respective convolutions and the sides ofthe convolutions in face-to-face contact therewith having adhesiveengagement of varying degree, said degree of adhesive engagementincreasing from the core outwardly throughout the roll in accordancewith a predetermined pattern, said pattern of adhesive engagementrequiring, in the unwinding of the roll, a tension to effect adhesivedisengagement between the respective convolutions which is less for theconvolutions near the inner part of the roll than for those near theouter part of the roll.

2. A roll of normally tacky and pressure sensitive adhesive tape withadjacent convolutions in face-to-face contact and including a Wovencloth backing having on one side, a pressure sensitive adhesive coatingand, on the other side, an absence of any coating that would tendsubstantially to alter the discontinuity normally presented by such acloth backing by virtue of its weave, said roll of tape between theadhesive coated sides of the respective convolutions and the sides ofthe convolutions in face-to-face contact therewith having adhesiveengagement of varying degree, said degree of adhesive engagementincreasing from the core outwardly throughout the roll in accordancewith a predetermined pattern, said pattern of adhesive engagementrequiring, in the unwinding of the roll, a tension to efiect adhesivedisengagement between the respective convolutions which is less for theconvolutions near the inner part of the roll than for those near theouter part of the roll, and said convolutions near the outer part of theroll being such as to impart substantial resistance to deformation ofthe roll under normal handling.

3. A roll of normally tacky and pressure sensitive adhesive tape withadjacent convolutions in face-to-face contact and including a wovencloth backing having on one side, a pressure sensitive adhesive coatingand, on the other side, an absence of any coating that would tendsubstantially to alter the discontinuity normally presented by such acloth backing by virtue of its weave, said roll of tape between theadhesive coated sides of the respective convolutions and the sides ofthe convolutions in face-to-face contact therewith having adhesiveengagement of varying degree, said degree of adhesive engagementincreasing from the core outwardly throughout the roll in accordancewith a predetermined pattern, said 4 pattern of adhesive engagementrequiring, in the unwinding of the roll, a tension to effect adhesivedisengagement between the respective convolutions which decreasessubstantially uniformly from the outer to the inner ends of the tape inthe roll.

4. A roll of normally tacky and pressure sensitive adhesive tape withadjacent convolutions in face-to-face contact and including a wovencloth backing having on one side, a pressure sensitive adhesive coatingand, on the other side, an absence of any coating that would tendsubstantially to alter the discontinuity normally presented by such acloth backing by virtue of its weave, said roll of tape between theadhesive coated sides of the respective convolutions and the sides ofthe convolutions in face-to-face contact therewith having adhesiveengagement of varying degree, said degree of adhesive engagementincreasing from the core outwardly throughout the roll in accordancewith a predetermined pattern, said pattern of adhesive engagementrequiring, in the unwinding of the roll, a tension to effect adhesivedisengagement between the respective convolutions which is less for theconvlutions near the inner part of the roll than for those near theouter part of the roll, said convolutions near the outer part of theroll being such as to impart substantial resistance to deformation ofthe roll under normal handling and said roll throughout being devoid ofspacing between convolutions.

5. A roll of pressure-sensitive adhesive-coated fabricbacked tape havingunwinding tensions no greater near the core than throughout the rest ofthe roll, the exterior convolutions of said roll being firmer and moreresistant to deformation than the interior convolutions of said roll.

6. A roll of pressure-sensitive adhesive cloth-backed tape having anunwinding tension which is less near the core than toward the outerperiphery of said roll, the exterior convolutions of said roll beingmore resistant to deformation than the interior convolutions of saidroll.

7. A roll of pressure-sensitive adhesive tape in accordance with claim 6wherein the unwinding tension decreases substantially uniformly from theexterior convolutions of the roll toward the interior convolutionsthereof.

8. A roll of pressure-sensitive adhesive-coated fabric tape wherein theouter convolutions of said roll are firmer than the inner convolutionsof said roll, the outer convolutions being more compressed than theinner convolutions particularly near its core.

References Cited in the tile of this patent UNITED STATES PATENTS2,349,710 Evans May 23, 1944 2,350,369 Sampair et al. June 6, 19442,372,336 Olsen Mar. 27, 1945 2,680,573 Monkley June 8, 1954 2,702,772Pronio ...e Feb. 22, 1955

1. A ROLL OF NORMALLY TACKY AND PRESSURE SENSITIVE ADHESIVE TAPE WITHADJACENT CONVOLUTIONS IN FACE-TO-FACE CONTACT AND INCLUDING A WOVENCLOTH BACKING HAVING ON ONE SIDE, A PRESSURE SENSITIVE ADHESIVE COATINGAND, ON THE OTHER SIDE,AN ABSENCE OF ANY COATING THAT WOULD TENDSUBSTANTIALLY TO ALTER THE DISCONTINUITY NORMALLY PRESENTED BY SUCH ACLOTH BACKING BY VIRTUE OF ITS WEAVE, SAID ROLL OF TAPE BETWEEN THEADHESIVE COATED SIDES OF THE RESPECTIVE CONVOLUTIONS AND THE SIDES OFTHE CONVOLUTIONS IN FACE-TO-FACE CONTACT THERWITH HAVING ADHESIVEENGAGEMENT OF VARYING DEGREE, SAID DEGREE OF ADHESIVE ENGAGEMENTINCREASING FROM THE CORE OUTWARDLY THROUGHOUT THE ROLL IN ACCORDANCEWITH A PREDETERMINED PATTERN, SAID PATTERN OF ADHESIVE ENGAGEMENTREQUIRING, IN THE UNWINDING OF THE ROLL, A TENSION TO EFFECT ADHESIVEDISENGAGEMENT BETWEEN THE RESPECTIVE CONVOLUTIONS WHICH IS LESS FOR THECONVOLUTIONS NEAR THE INNER PART OF THE ROLL THAN FOR THOSE NEAR THEOUTER PART OF THE ROLL.